In the design of a battery, one factor that influences the performance of a battery is the compression pressure on the separators between the positive and negative electrode plates. If insufficient pressure is applied, detachment of the separator can occur and cause a decrease in performance. High compression, however, can lead to insufficient amount of absorbed electrolyte and can have the same detrimental effect.
A plurality of electrode plates is referred to as a cell stack. A cell stack is contained in a battery container or "jar". A jar is usually a molded part, made from plastic which is resistant to the electrolyte. For easy release of the mold, the inside of the jar is designed with a taper, being wider at the top and narrower at the bottom. This tapered design can lead to a non-uniform distribution of compression pressure on the stack, being low at the top and high at the bottom. As a result, because of this non-uniform distribution, the top of the cell stack is prone to detachment.
A need has thus arisen for a grid design for battery plates and an apparatus for providing a uniform compression pressure over the entire height of the battery cell stack.